In a refrigerator the power rating impressed on the compressor is 1.2 kW. The circulating wire in evaporator is 5 kW and the cooling water took away 10 kW from condenser coil. The operating temperatures range is 18ºC and 0ºC and their corresponding latent heats are 170 kJ/kg and 230 kJ/kg and the difference between the liquid energy is 35 kJ/kg. Find the actual COP of the system (2) relative COP, assuming the vapor is just dry and saturated at the end of the compression.

In a refrigerator the power rating impressed on the compressor is 1.2 kW. The circulating wire in evaporator is 5 kW and the cooling water took away 10 kW from condenser coil. The operating temperatures range is 18ºC and 0ºC and their corresponding latent heats are 170 kJ/kg and 230 kJ/kg and the difference between the liquid energy is 35 kJ/kg. Find the actual COP of the system (2) relative COP, assuming the vapor is just dry and saturated at the end of the compression.

Refrigeration and Air Conditioning Technology (MindTap Course List)

8th Edition

ISBN:9781305578296

Author:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill Johnson

Publisher:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill Johnson

Chapter45: Domestic Refrigerators And Freezers

Section: Chapter Questions

Problem 12RQ: Refrigerators currently being manufactured in the United States are using______as their refrigerant.

See similar textbooks

Similar questions

A refrigerator using fluid-134a as a work fluid is used to keep the cooling medium at -25 oC. The refrigerator releases the waste heat, which enters the condenser at 18 oC with a flow of 0.30 kg / s and from the condenser at 26 oC to the cooling water. The refrigerant enters the condensate at a pressure of 1.2 MPa and 50 oC, and leaves the condenser at 40 oC at the same pressure. Find a) the mass flow rate of the refrigerant, b) the power consumed by the compressor, c) the COP value, and d) the minimum power that the compressor will consume for the same cooling load.They watch the specific heat of water as ?? = 4.22 ?? / ???.
Assume that the heat engine receives steam at 782 Kelvin and releases the excess portion at 31 degrees Celsius. What would the heat engine's total efficiency be?
A refrigerator using R-134a as the refrigerant is used to keep a space at - 10°C by rejecting heat to ambient air at 22 °C. R-134a enters the compressor at 140 kPa as a saturated vapor and leaves at 800 kPa and 70 °C. The refrigerant leaves the condenser as a saturated liquid. The rate of cooling provided by the system is 2600 W. Determine (a) the mass flow rate of R-134a, (b) the COP, (c) the exergy destruction in each component of the cycle, (d) the second-law efficiency of the cycle, and (e) the total exergy destruction in the cycle.
Steam is supplied to a fully loaded 100-hp turbine at 276 psia with u1=1,220.3 Btu/lbm, v1=3.65 ft3/lbm and υ1=466 ft/s. Exhaust is at 3 psia with u2=943 Btu/lbm, v2=392 ft3/lbm and υ2=1,128 ft/s. The heat loss from the steam in the turbine is -10 Btu/lbm. Neglect potential energy change and determine the work per lbm steam (unit should be ft⋅lbf/lbm ).
A commercial refrigerator using R-134a as a refrigerant is used to keep the cooled environment at -35'C. The refrigerator releases the waste heat to the cooling water that enters the condenser at 18'C with a flow of 0.25 kg / s and leaves the condenser at 26'C. The refrigerant enters the condenser at a pressure of 1.2 MPa and a temperature of 50'C, and leaves the condenser at the same pressure and supercooled at 5 ₒC. Since the compressor consumes 3.3 kW of power, a) Mass flow rate of the refrigerant, b) Cooling load and COP value c) Calculate the minimum power consumed by the compressor for the same cooling load.
Refrigerant-134a enters the compressor of a refrigerator as superheated vapor at 0.14 MPa and -10oC at rate of 0.05 kg/sec and leave at 0.8 MPa and 50oC. The refrigerant is cooled in the condenser to 26oC and 0.72MPa and is throttled to 0.15MPa. Determine (a) the rate of heat removal from the refrigerated space and the power input to the compressor, (b) the isentropic efficiency of the compressor and (c) the coefficient of performance.
Derive an expression for the COP of a completely reversible refrigerator in terms of the thermal energy reservoir temperatures, TL and TH.
A commercial refrigerator using R-134a as the refrigerant is used to keep the refrigerated environment at -35 ° C. The refrigerator releases the waste heat to the cooling water entering the condenser at 18 ° C with a flow of 0.25 kg / s and leaving the condenser at 26 ° C. The refrigerant enters the condenser at a pressure of 1.2 MPa and a temperature of 50 ° C, and leaves the condenser at the same pressure and supercooled at a temperature of 5 ° C. Since the compressor consumes 3.3 kW of power, Calculatea) Mass flow rate of the refrigerant,b) Cooling load and COP valuec) The least power consumed by the compressor for the same cooling load
A heat pump using refrigerant-134a heats a house by using underground water at 8°C as the heat source. The house is losing heat at a rate of 60,000 kJ/h. The refrigerant enters the compressor at 280 kPa and 0°C, and it leaves at 1 MPa and 60°C. The refrigerant exits the condenser at 30°C. Determine (a) the power input to the heat pump, (b) the rate of heat absorption from the water, and (c) the increase in electric power input if an electric resistance heater is used instead of a heat pump. Answers: (a) 3.55 kW (b) 13.12 kW (c) 13.12 kW
A refrigerator is used to keep the cold space at 5 °C by rejecting 8 kJ/s of heat by the condenser tothe outdoor air at 25 °C. If the compressor consumes 3 kJ/s of power, determinei. the rate of heat removed from the cold space (kJ/s),ii. the COP of the refrigeratoriii. the minimum power input to the compressor for the same rate of heat removed (kJ/s), andiv. draw the schematic of the refrigerator as a reversed heat engine.
An air compressor that is water-cooled handles 0.15m3/s of air that enters at 96.8kPa and 25°C and leaves at 485kPa and 139°C. 11kg/hr of cooling water enters the jacket at 16°C and leaves at 20°C. Solve for the compressor power. 26.71kW 29.32kW 27.69kW 22.43kW
Refrigerant-134a enters the condenser of a residential heat pump at 800 kPa and 35°C at a rate of 0.018 kg/s and leaves at 800 kPa as a saturated liquid. If the compressor consumes 1.2 kW of power, determine the COP of the heat pump?